Objectives:Half of veterans who use VHA outpatient care also are eligible for Medicare. Dual system use may improve care by increasing options or it may result in poorer outcomes because of fragmented care. Chronic lower limb wounds are a common precursor to amputations, many of which might be prevented with appropriate treatment. Our objective was to assess whether dual system use of VHA and Medicare was associated with chronic lower limb wound healing.

Methods:We conducted a retrospective cohort study of 227 Medicare-enrolled veterans in the Pacific Northwest who had an incident, chronic lower limb wound between October 1, 2006 and September 30, 2007. All wounds were identified through VHA chart review and followed for up to one year or until the wound resolved (healed, amputated, or veteran died). We searched Medicare claims to identify dual system wound care during follow-up using ICD-9 codes. We considered veterans to be VHA-exclusive users until the date of their first wound-related Medicare claim; thereafter, veterans were classified as dual users. We used a time-varying measure of dual use in a competing risks proportional hazards model to compare wound healing among VHA-exclusive and dual users.

Results:Veterans who used VHA wound care exclusively (82.9%) and those who used both Medicare and VHA (dual users; 18.1%) were similar, with some differences in wound etiology and lower limb wound and amputation history. After adjusting for veteran demographic, health history, and wound-related characteristics, dual use was associated with a significantly lower hazard of wound healing compared to VHA-exclusive use (HR = 0.56, 95%CI: 0.37-0.85, p = 0.007). Hazards for the competing risks, amputation (HR = 6.39, 95% CI: 2.05-19.95, p = 0.001) and death (HR = 4.62, 95%CI: 1.59-13.44, p = 0.005), were significantly higher for dual users compared to VHA-exclusive users. This association was robust to several sensitivity analyses.

Implications:Using a wound care-specific measure of dual use, we found dual use was associated with substantially poorer wound healing.

Impacts:Coordination of wound care across systems is important to improve wound-specific outcomes among dual users of VHA and Medicare. Future research should focus on identifying patient and system-level factors that will improve cross-system coordination.